Is a 1156 = 7506 bulb?


Newly Enlightened
Feb 12, 2012
Hi all, first post. I was curious to know if a 1156 bulb is the same as a 7506 bulb. I recently replaced my rear tail light lenses on my 2006 BMW with a set of Blackline lenses. The stock lenses use standard 7506 bulbs since the rear turn signals are red. The new lenses are a clear smoke color and will require a amber colored bulb. The only ones I have found are the 1156 mirrored bulbs. Will they work??

Any help is appreciated. Thanks.


Mar 26, 2004
7506 is Osram's number for a type P21W bulb. P21W and 1156 are very similar. They aren't identical, but they are functionally interchangeable in many cases as long as the 1156 one uses has a nickel-plated base and not a plain brass one. If you are forced for some reason to use a plain brass base bulb in a socket intended for a P21W, apply silicone dielectric grease to the base before installing the bulb.

Those Blackline lenses of yours were meant for use with a different bulb holder assembly, which accepts a PY21W bulb rather than a P21W in the turn signal compartment. PY21W is the amber version of P21W, and its base pins are placed differently than P21W so that those two bulbs can't be interchanged (a European requirement). There are legitimate "invisible" (silver/chrome) versions of PY21W from Osram and Philips.

Do not use any of the off-brand (non-Osram, non-Philips) silver/chrome bulbs such as the ones you've linked. None of them produce an adequate/safe/legal amount of light. They are all crude knockoffs of a Philips product called "Silver Vision" that was never expanded beyond PY21W. The real bulbs contain a fascinating amount of technology. The fakes you linked to...don't, and the result is grossly inadequate amount of light. They aren't safe, and will make your signals illegally dim.

For now, use a good brand of 1156A or 1156NA (same bulb; some makers use one designation and some use the other). If no nickel base, use the silicone grease. Meanwhile, hunt for a set of the correct bulb holders for use with your new lenses, then you can safely use the real "invisible" bulbs if you want.

The other get-by option is to go ahead and buy the Philips SilverVision or Osram Diadem invisible PY21W and file down one of its two index pins so that it can be installed in the original bulb holder. If you do this, take careful note of the filament orientation of the original P21W bulb and pay close attention to what you are doing, comparing the P21W and PY21W pins so you file off the pin that will leave the pin that will put the PY21W in the same correct filament orientation.

Philips SilverVision PY21W bulb is here.

Osram Diadem PY21W bulb is here.

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